Efficient alternate RWA protocol for WDM networks

Existing methodologies in WDM networks, generally uses either lightpath distance or network congestion to identify optimal and backup lightpaths. In our paper, we have designed an efficient alternate RWA protocol (EARP) which considers both congestion and route distance so as to improve the network performance. On arrival of a request the source node sends control signals through all the paths to the destination node. In this process, the number of free continuous wavelengths and conflict information are collected at the destination. Then, the lightpaths are computed based on this information and the precomputed distance information. A subset of wavelengths in the optimal lightpath is considered at the destination node for the reservation on the basis of conflict information. Backup lightpath is used for survivability. The selection of backup lightpath is done in such a way that there is no shared link between the primary and backup lightpath but it can be shared with another backup lightpath. By simulation results, we showed that our proposed protocol has lower blocking probability than the existing.